libstdc++: Do not set eofbit eagerly in operator>>(istream&, char(&)[N])

Similar to the bugs I fixed recently in istream::ignore, we incorrectly
set eofbit too often in operator>>(istream&, string&) and
operator>>(istream&.  char(&)[N]).

We should only set eofbit if we reach EOF but would have kept going
otherwise. If we've already extracted the maximum number of characters
(whether that's because of the buffer size or the istream's width())
then we should not set eofbit.

libstdc++-v3/ChangeLog:

	* include/bits/basic_string.tcc
	(operator>>(basic_istream&, basic_string&)): Do not set eofbit
	if extraction stopped after in.width() characters.
	* src/c++98/istream-string.cc (operator>>(istream&, string&)):
	Likewise.
	* include/bits/istream.tcc (__istream_extract): Do not set
	eofbit if extraction stopped after n-1 characters.
	* src/c++98/istream.cc (__istream_extract): Likewise.
	* testsuite/21_strings/basic_string/inserters_extractors/char/13.cc: New test.
	* testsuite/21_strings/basic_string/inserters_extractors/wchar_t/13.cc: New test.
	* testsuite/27_io/basic_istream/extractors_character/char/5.cc: New test.
	* testsuite/27_io/basic_istream/extractors_character/wchar_t/5.cc: New test.

diff --git a/libstdc++-v3/include/bits/basic_string.tcc b/libstdc++-v3/include/bits/basic_string.tcc
index e370f439390f94903988478a3c9bf36c169d94f5..75218a4061096b7843e405448513ef37cdf019f6 100644 (file)
--- a/libstdc++-v3/include/bits/basic_string.tcc
+++ b/libstdc++-v3/include/bits/basic_string.tcc
@@ -1518,7 +1518,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
                }
              __str.append(__buf, __len);
 
-             if (_Traits::eq_int_type(__c, __eof))
+             if (__extracted < __n && _Traits::eq_int_type(__c, __eof))
                __err |= __ios_base::eofbit;
              __in.width(0);
            }

diff --git a/libstdc++-v3/include/bits/istream.tcc b/libstdc++-v3/include/bits/istream.tcc
index b8f530f6ef5061f1dbf59057adb14bf169bc40a3..022db9383e944a0ba83bc82f9e15e71208ad2c23 100644 (file)
--- a/libstdc++-v3/include/bits/istream.tcc
+++ b/libstdc++-v3/include/bits/istream.tcc
@@ -1023,7 +1023,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
                  ++__extracted;
                  __c = __sb->snextc();
                }
-             if (_Traits::eq_int_type(__c, __eof))
+
+             if (__extracted < __num - 1
+                 && _Traits::eq_int_type(__c, __eof))
                __err |= ios_base::eofbit;
 
              // _GLIBCXX_RESOLVE_LIB_DEFECTS

diff --git a/libstdc++-v3/src/c++98/istream-string.cc b/libstdc++-v3/src/c++98/istream-string.cc
index c59f2ce0b34743d736798c251b72439d31a775d1..bfd7389e2e2e15bbe524c5642c9fd05f86b5a276 100644 (file)
--- a/libstdc++-v3/src/c++98/istream-string.cc
+++ b/libstdc++-v3/src/c++98/istream-string.cc
@@ -93,7 +93,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
                    }
                }
 
-             if (__traits_type::eq_int_type(__c, __eof))
+             if (__extracted < __n && __traits_type::eq_int_type(__c, __eof))
                __err |= ios_base::eofbit;
              __in.width(0);
            }

diff --git a/libstdc++-v3/src/c++98/istream.cc b/libstdc++-v3/src/c++98/istream.cc
index 7a48779d337ab43e53670f1e1b6764795994bf1f..79a77b8475a383ffe8b4cae338879d78623d5144 100644 (file)
--- a/libstdc++-v3/src/c++98/istream.cc
+++ b/libstdc++-v3/src/c++98/istream.cc
@@ -261,7 +261,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
                    }
                }
 
-             if (__traits_type::eq_int_type(__c, __eof))
+             if (__extracted < __num - 1
+                 && __traits_type::eq_int_type(__c, __eof))
                __err |= ios_base::eofbit;
 
              // _GLIBCXX_RESOLVE_LIB_DEFECTS

diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/inserters_extractors/char/13.cc b/libstdc++-v3/testsuite/21_strings/basic_string/inserters_extractors/char/13.cc
new file mode 100644 (file)
index 0000000..f54042a
--- /dev/null
+++ b/libstdc++-v3/testsuite/21_strings/basic_string/inserters_extractors/char/13.cc
@@ -0,0 +1,55 @@
+// Copyright (C) 2020 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-do run }
+
+#include <string>
+#include <sstream>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+  const std::string str = "1234";
+  std::istringstream in(str);
+  std::string buf;
+  in.width(4);
+  in >> buf;
+  VERIFY( !in.eof() ); // should stop after reading 4 chars
+  VERIFY( buf == str );
+}
+
+struct CT : std::char_traits<char> { };
+
+void
+test02()
+{
+  const std::basic_string<char, CT> str = "1234";
+  std::basic_istringstream<char, CT> in(str);
+  std::basic_string<char, CT> buf;
+  in.width(4);
+  in >> buf;
+  VERIFY( !in.eof() ); // should stop after reading 4 chars
+  VERIFY( buf == str );
+}
+
+int
+main()
+{
+  test01();
+  test02();
+}

diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/inserters_extractors/wchar_t/13.cc b/libstdc++-v3/testsuite/21_strings/basic_string/inserters_extractors/wchar_t/13.cc
new file mode 100644 (file)
index 0000000..f18e2cb
--- /dev/null
+++ b/libstdc++-v3/testsuite/21_strings/basic_string/inserters_extractors/wchar_t/13.cc
@@ -0,0 +1,55 @@
+// Copyright (C) 2020 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-do run }
+
+#include <string>
+#include <sstream>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+  const std::wstring str = L"1234";
+  std::wistringstream in(str);
+  std::wstring buf;
+  in.width(4);
+  in >> buf;
+  VERIFY( !in.eof() ); // should stop after reading 4 chars
+  VERIFY( buf == str );
+}
+
+struct WT : std::char_traits<wchar_t> { };
+
+void
+test02()
+{
+  const std::basic_string<wchar_t, WT> str = L"1234";
+  std::basic_istringstream<wchar_t, WT> in(str);
+  std::basic_string<wchar_t, WT> buf;
+  in.width(4);
+  in >> buf;
+  VERIFY( !in.eof() ); // should stop after reading 4 chars
+  VERIFY( buf == str );
+}
+
+int
+main()
+{
+  test01();
+  test02();
+}

diff --git a/libstdc++-v3/testsuite/27_io/basic_istream/extractors_character/char/5.cc b/libstdc++-v3/testsuite/27_io/basic_istream/extractors_character/char/5.cc
new file mode 100644 (file)
index 0000000..984f881
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_istream/extractors_character/char/5.cc
@@ -0,0 +1,54 @@
+// Copyright (C) 2020 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-do run }
+
+#include <sstream>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+  const std::string str = "1234";
+  std::istringstream in(str);
+  char buf[6];
+  in.width(5);
+  in >> buf; // stops after reading 4 chars, doesn't reach EOF
+  VERIFY( !in.eof() );
+  VERIFY( buf == str );
+}
+
+struct CT : std::char_traits<char> { };
+
+void
+test02()
+{
+  const std::string str = "1234";
+  std::basic_istringstream<char, CT> in(str.c_str());
+  char buf[6];
+  in.width(5);
+  in >> buf; // stops after reading 4 chars, doesn't reach EOF
+  VERIFY( !in.eof() );
+  VERIFY( buf == str );
+}
+
+int
+main()
+{
+  test01();
+  test02();
+}

diff --git a/libstdc++-v3/testsuite/27_io/basic_istream/extractors_character/wchar_t/5.cc b/libstdc++-v3/testsuite/27_io/basic_istream/extractors_character/wchar_t/5.cc
new file mode 100644 (file)
index 0000000..03bbcad
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_istream/extractors_character/wchar_t/5.cc
@@ -0,0 +1,54 @@
+// Copyright (C) 2020 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-do run }
+
+#include <sstream>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+  const std::string str = "1234";
+  std::istringstream in(str);
+  char buf[6];
+  in.width(5);
+  in >> buf; // stops after reading 4 chars, doesn't reach EOF
+  VERIFY( !in.eof() );
+  VERIFY( buf == str );
+}
+
+struct WT : std::char_traits<wchar_t> { };
+
+void
+test02()
+{
+  const std::wstring str = L"1234";
+  std::basic_istringstream<wchar_t, WT> in(str.c_str());
+  wchar_t buf[6];
+  in.width(5);
+  in >> buf; // stops after reading 4 chars, doesn't reach EOF
+  VERIFY( !in.eof() );
+  VERIFY( buf == str );
+}
+
+int
+main()
+{
+  test01();
+  test02();
+}